We study kink oscillations of a straight magnetic tube in the presence of siphon flows. The tube consists of a core and a transitional or boundary layer. The flow velocity is parallel to the tube axis, has constant magnitude, and confined in the tube core. The plasma density is constant in the tube core and it monotonically decreases in the transitional layer to its value in the surrounding plasma. We use the expression for the decrement/increment previously obtained by Ruderman and Petrukhin (Astron. Astrophys. 631, A31, 2019) to study the damping and resonant instability of kink oscillations. We show that, depending on the magnitude of siphon-velocity, resonant absorption can cause either the damping of kink oscillations or their enhancement. There are two threshold velocities: When the flow velocity is below the first threshold velocity, kink oscillations damp. When the flow velocity is above the second threshold velocity, the kink oscillation amplitudes grow. Finally, when the flow velocity is between the two threshold velocities, the oscillation amplitudes do not change. We apply the theoretical result to kink oscillations of prominence threads. We show that, for particular values of thread parameters, resonant instability can excite these kink oscillations.

我们研究了存在虹吸流时直磁管的扭结振荡。管由芯和过渡层或边界层组成。流速平行于管轴，大小恒定，并限制在管芯内。管芯中的等离子体密度是恒定的，并且它在过渡层中单调降低到周围等离子体中的值。我们使用先前由 Ruderman 和 Petrukhin ( Astron. Astrophys. 631, A31, 2019) 研究扭结振荡的阻尼和共振不稳定性。我们表明，根据虹吸速度的大小，共振吸收可以导致扭结振荡的阻尼或增强。有两个阈值速度：当流速低于第一个阈值速度时，扭结振荡减弱。当流速高于第二阈值速度时，扭结振荡幅度增大。最后，当流速在两个阈值速度之间时，振荡幅度不变。我们将理论结果应用于突出线的扭结振荡。我们表明，对于螺纹参数的特定值，共振不稳定性可以激发这些扭结振荡。